Process of electric welding.



'PATENTED MAR. 12,1907.

L. S. LAUHMAN. PROCESS OF ELEGTRIG WELDING.

APPLICATION FILED OCT. 28.1905.

In ventor:

' Wm, 7 M

I I am nevertheless not to be understood as' UNITED s'rA'rEs PATENT crass. I

LAURENCE s. LACHMAN,.OF NEW YORK,

N. Y., ASSIGNOR TO STANDARD PULLEY MANUFACTURING COMPANY, ATCORPORATION OF NEW YORK.

PROCESS OF susc-rmo WELDING.

Specification of Letters Patent,

Batented Maren 12, 1907.

clination filed October 22.1905. Serial No. 284,906.

T his invention relates to improved proc-.

cs -cs of electric welding for welding two sheets metal together.

The invention may be applied tothe construction of all kinds of utensils, pulleys, wheels, sheaves, pulley-frames, and other structures which two metal parts are to be secured together, whereby the parts oi the structures may be securely united to each other nithout the use of rivets, bolts, keys, and without interlocking connections.

. W hile i have specified certain-named devices to which the inventionrelates and to which the process is particularly applicable,

limiting this invention to such devices, be'- cause the process may be used in any connection in which it is applicable.

Further objects of the invention will hereinafter appear; and to these ends the invention consists of the process of electric welding for carrying out the above objects embodying the steps hereinafter fully described and claimed in this specification.

Suitable apparatus for carrying out the rocess is illustrated in the accompanying draeings, in which 3 riguie 1 1s a vertical sectional view of a suitable die or press and the parts of a sheet-- metal utensil which are to be welded together electrically. Fig. 2 is a top plan view of the two sheets of metal before being placed in the press. Fig. 3 is a vertical sectional view of a portion of a utensil and a handle to be. welded thereto; and Fig. 4 is a vertical sectional view of the portion of the utensil and the handle after welding, showing a section through the weld.-

This invention is in some respects an improvement upon the processes disclosed in my copending applications, Serial Nos. 233,109 and 251,712,, in which I disclose methods of making sheet-metal structures having portions of sheet metal welded ,together electrically by means of points or projections. I have heretofore proposed to weld two sheets of metal of the same thickness together by forming a projection on one sheet and placing it against the flat. surface of the other sheet, passing a currentof electricity through. the sheets of metal. and pressing the sheets together as the projection fuses.

have also proposed to form projections on both sheets of metal and place the projecrent of electricity through the sheets and said projections, thereby fusing both. projections and pressing the sheets of metal together to complete the Weld. In these cases substantially the same thickness, and I have found that if said sheets are greater than a given thickness a point or projection on one sheet will not become securely welded to the other thick. sheet'when the point is placed upon the flat surface of saidsheet, because the flat sheet without the point apparently does not become sufficiently hot or fused to form a perfect weld and the parts may generally be pried apart, because the weld is superficial. On the other hand, I have found that when the two sheets of metal are excessively thin and each is provided with points andv the points are placed one upon the other the resistance afforded to the current is so great that not only the points themselves, but portions of the thin sheets of metal, are actually fused to such an extent that an imperfect weld is formedthet is, the metal is burnt and the points of fusion are weak.

I have discovered that a perfect weld may be formed between a thin sheet of metal and another sheet of substantially thick metal by forming points or projections upon the thicker sheet and placing. these points directly upon the flat surface of the thinner through the two sheets and throu h the points and pressing the two sheets 0 metal together as the points are fused. By'using a thin sheet of metal andanother substantially about the proper amountof resistance is. afforded to-thecurrent to fuse the points and sheet of metal, because theipoints or projecsheet, then passing a current of electricity.

heat the thin sheet at the points of contactsufiicien'tly to form a perfect weld which can, hardly be seen on the reverse side of the thintions opposite each other, then passa cur-.

the sheets of metal have generally been of thicker sheet having points and placing the points on the flat surface I have found that x tions doinot project through the thin sheet. Upon taking a 'section'through one of the fwelds a perfect weld is found. I

In accordance with this invention the sheet of metal A of Fig. '1- is placed upon the die B, and the thick sheet'of metal C, .pro-= vided with projections or points D, only one. of whichv is shown by way of illustration and.

. E brought down upon the two sheets at the which may be punched out of'the sheet, is placed upgn the thin sheet and the upper die same time that a current of electricity is passed through the dies and'the sheets of inetal from' the generator F, connected'in circ'uit and provided with a. suitable switch G. 1

- Fig. 2 is a top plan view: of a sheet A; and thethick sheetC, placed on tpp thereof,

and the point or projection D. This process is found to have great utility in welding handles and, other earsor projections upon uten sils of all kinds and forwelding handles on shovels or in any case in which a thick part is to be welded to a thin sheet; In Fig. 3, H represents a thin sheet of finetal, which may be'a portion of a cooking utensil, as a pot or pan, and I is'ahandle of substintially thicker "metal to be welded thereto,- provided with points or. projections J of which there may be any desired numbei'. In Fig\ 4 a section is taken through the weld after the weld has been completed, fronr which itwill be seen that the sheet H and the f thicker handle or projection I are perfectly weliei at the point K and formed into one integral whole.

' .It is of course possible to weld two substan- "tially thiclrslieetstogether bymeans ofpoints orprojections on each placei opposite each other and one on the other, ecause the points wiilfuse and weld under pressure when the 'current is applied-and the metai will be of-suchthickness that the welds will not tear meltedand burnt at the points'otcontactf Accfor'd1ng to my present process, however,

out;. but it is not adyisable. to-provide points L on both a thick sheet and a thin sheet, because. the resistance is so, high that the thin sheet. is

' for weliing thickand .thin "sheets theflthin sistance of the. thic .tainecl. According to my:

. sheet is-not'burnt and perfect welds are-ob present process I the. re-. metal is sufiicient' to'enable the p'oints to embed themselves in the" heated thin metah therebyzmaking a perfect weld without projecting through on the other side of the'thin metaLi The, points in" 1 corporate themselves in the metal. of the V fectlysatisfactory results have beenpbtained thinfiheet, forming a truewld, and

in Welding thick' metal three or four gages 5o heavier than the thin metal.

I The points of projections formed upon one 'ofthe sheets in carrying out this process are, I

asshown, widely separated and independent one'from the other, and the series of points is of substantially the same total efi'ective contact area as the total area of the final welds formed" at the points, According to this mode of operation the plates may be said to is not to be limited to all the details of description.

I therefore claim, and desire to obtain by Letters Patent, the following:

1. The process of electrically welding a thin piece of sheet metal to another relatively thicker piece, which consists in providing projecting portions upon the thic'ker piece of metal, placing said projections against the surface of the thin sheet of metal, passing a current through said sheets of metal and the projecting portions, thereby fusing said por- 'tions and heating the thin sheet of metal at the points of contact and simultaneously forcing the two sheets of metal together to securely weld one to the other.

may be used without others, and the process 2'. The process of electrically welding a I .piece of substantiallj thinmctal to another piece of relatively thicker metal, which consists'in'pi'oviding a point or projecting portion-upon the thick piece of metal, placing said thick piece upon the thin piece with the said point .or projection of said thick piece in ty thrpugh' sai pieces'of'metal' and through the point orprojection, thereby fusing said I point and heating the-thin piece of metal forming a true weld and; simultaneously forcing thetwo pieces of metal. together to securely weld-one to the other.

Intestimony whereof I have signed this specification. in the ing witnessest.

- LAURENCE s. LACHMAN. Witnesses:

v 0. A. Fos'rnn,

A. OBRIEN.

:direct contact with-the surface of the thin .piece of metal, assing a current of electricpoint of" contact and incorporating "said ploh'nt in the metal of the thin piece IIC presence of two subscrib- I 

